In the development of micro components made of silica glass and used for highly-functional/highly-integrated devises, it is required to establish fabrication techniques and production processes of the silica glass, ranging from a sub-micro order to a nano order. Silica glass has a variety of excellent physical properties such as low expansion, heat resistance, chemical resistance, and insulation; and also has a high light transmittance in a vacuum ultraviolet to near-infrared wavelength range. As such, silica glass is expected to serve as a base material not only in the fields of information processing and communication but also in the next-generation photonics industry. Further, silica glass has a high viscosity even in a high-temperature region; thus can be formed into a desired shape by repeatedly performing local heating on the silica glass (see Patent Documents 1 and 2, for example).